The importance of physical fitness is increasingly being stressed in today's society. However, due to time constraints imposed by today's lifestyles as well as limited space for performing outdoor activities, more and more people are turning to health facilities to exercise. These facilities usually have exercise equipment such as rowing machines, stationary bicycles, stair machines, and treadmills. The majority of equipment available is designed for strengthening muscles and for increasing aerobic capacity. Machines to stretch muscles and thus to increase flexibility are generally not well represented at most health clubs. Increasing flexibility is important to reduce injuries due to tearing of muscles tissues; to increase the range of motion when doing a specific activity; to promote muscle relaxation; and to increase metabolism in muscles, joints and associated connective tissues. Exercises to increase flexibility are also used in the treatment of paralysis, orthopaedic problems and neuromuscular disabilities.
Machines that increase flexibility in the groin and quadracept muscles are described in U.S. Pat. No. 4,647,040 (Ehrenfried), U.S. Pat. No. 4,619,454 (Walton) and U.S. Pat. No. 4,826,158 (Fields). These devices are intended to improve flexibility by spreading apart the users legs into a split position.
U.S. Pat. No. 4,877,239 (Gregario Del Rosa) describes a thigh muscle stretching device wherein the muscles are stretched by spreading apart the users legs via a pair of elongated rod members which operate using a crank and worm gear mechanism.
U.S. Pat. No. 4,819,936 (Mueller) and U.S. Pat. No. 4,750,741 (Smalanovich) describe machines for stretching the back.
These prior art devices generally apply a force to the users limbs or body parts to spread them apart, which can cause injury. Also these devices do not provide any feedback as to the position of the body part being stretched or the force exerted on the muscle so that the exercise can be accurately repeated and the degree of stretching can be safely increased.
Exercises to increase flexibility that do not require an exercise machine have been described by the present invention in "Scientific Stretching for Sport (3S) Method" Laurence E. Holt, Sports Research Limited, 1974. The 3S method involves stretching a body part, containing a muscle group to be stretched, to its maximum stretched position, and then attempting to push the body part in the opposite direction. This effort is resisted by a partner who does not permit the body part to move, thus causing an isometric contraction. After a given time interval, the isometric contraction is stopped and the opposite muscle group is contracted (concentric contraction) to stretch the body part to a position which is further than the initial starting position. However, disadvantages of this method are that a partner of equal or greater strength is required, and accurate repeatability of the exercise is difficult. If the partner does not adhere to the 3S methodology, an injury may result.